In general, the refrigerator is provided with a compressor for elevating a temperature and a pressure of low temperature, low pressure gaseous refrigerant to a high temperature and high pressure gaseous refrigerant, and a condenser for cooling and condensing the high temperature and high pressure gaseous refrigerant into liquidus refrigerant by using heat exchange with outdoor air.
In addition to this, the refrigerator is provided with a capillary tube having a diameter smaller than a diameter of other parts for decompressing the refrigerant introduced thereto from the condenser, and an evaporator for evaporating the refrigerant from the capillary tube to low temperature and low pressure refrigerant for absorbing heat from an inside of the refrigerator.
The refrigerator is also provided with a freezing chamber having cold air introduced thereto from the evaporator directly for maintaining a chamber temperature of about −18° C., and a refrigerating chamber having the cold air introduced thereto from the freezing chamber for maintaining a chamber temperature of about 0˜7° C.
There are a machinery room on a lower portion of a rear side of the refrigerating chamber having the compressor and the condenser mounted thereto, and a cold air supply unit in rear of the freezing chamber isolated therefrom with a rear wall thereof having a cooling fan for forced blow of the cold air from the evaporator to the freezing chamber and a defrosting heater for removing frost from a surface of the evaporator mounted thereto.
In the meantime, because, while a temperature of a surface of the evaporator is low, a temperature surrounding the evaporator is relatively high, dew drops are formed on the surface of the evaporator due to a temperature difference therebetween, and frozen by the temperature of the surface of the evaporator to form the frost.
There are two kinds of the defrosting heaters; one is a convection type heater which has no direct contact with the evaporator, and the other one is a radiation type heater which is in contact with the evaporator. Either one or both of them can be applicable to the refrigerator.
However, referring to FIG. 3, since the refrigerator with the radiation type heater has the compressor and the fan (not shown) turned off and only the heater 1 turned on for defrosting by using radiant heat, the refrigerator has a size limit of the evaporator 2 in a longitudinal direction, and a problem in that the defrosting can not be done appropriately if the evaporator 2 is located high.
Unexplained numerals in the drawing are heat exchanger tube 3, cooling fins 4, a liquid separator 5, and air (heat) flow V.